Jason Trawick

Her new song, "Work B––––," is a dance anthem, but Britney Spears says her upcoming album, which is due out in December, features more than a little heartbreak.

"It's the most personal album I've done," Spears, 31 admitted Friday on On Air with Ryan Seacrest. "After having a huge breakup this year, I had a lot to say in the studio, so it was really nice to have a therapy like that and to be able to share that with my fans … so it's a real personal album."

The "huge breakup" she's referring to is her January split with fiancé Jason Trawick. The pair, who were engaged for a year, began dating in 2009, but Trawick had long been a part of Spears life as a member of her management team.

She's left her gig as judge on The X Factor, her new puppy Hannah is gravely ill, and on Jan. 11 she announced she and fiancé Jason Trawick, 41, have called it quits after more than three years together.

While Spears, 31, told PEOPLE in an exclusive statement, "I'll always adore him, and we will remain great friends," a family source says the signer is "definitely upset about the split."

Britney Spears once believed in a fairy-tale ending for herself and Jason Trawick. But by mid-December, she was no longer wearing her engagement ring, and she knew it just wasn't going to happen, a source close to her family tells PEOPLE.

"Britney spent Christmas in L.A. with [sons] Preston and Jayden. Jason was around for parts of the holiday, but it was very obvious that they were not really together anymore," the source says.

"They were not affectionate and instead just seemed to keep things going for the boys' sake. Britney looked a bit gloomy and tense over the holidays."

Britney Spears still believes in "love" – at least when it comes to wearing it.

The pop star, 31 – whose failed engagement to Jason Trawick, 41, was announced on Friday – grabbed coffee in L.A. on Monday, sporting a black and white sweatshirt with the four-letter word displayed in large letters across the front.

The formerX Factor judge looked casual, wearing shades and her hair in a ponytail.

So what was behind the pair's decision to call off their engagement? According to a close source, Spears, 31, and Trawick, 41, both wanted "different things."

"There was no third party involved," says the source of the couple, who began dating in 2009. "Things haven't been ideal in their relationship for some time. There was a lot to work on before they could move forward and get married."

One of those things may have been Trawick's desire to maintain a life outside their relationship.

Jason Trawick has resigned as Britney Spears's conservator of her person, which once gave him the authority to make decisions about her general well-being, such as food, clothing, travel and medical care.

Britney Spears's sons don't see their mom as a superstar. They do, however, think she has super powers.

"They try to figure out where I go when I go to film X Factor. They're like, 'Mommy's going off to be a superhero.' And then I get back, and they just see me as Mommy," Spears, 30, tells Lucky magazine in its December cover story of her boys Preston, 7, and Jayden, 6.

"And then when I'm back working on the show, they say, 'Oh, Mommy's a superhero again!' "

As for the other man in the pop star's life, her fiancé Jason Trawick, Spears says he also doesn't mind seeing her without her "cape" on.